High-irradiance responses induced by far-red light in grass seedlings of the wild type or overexpressing phytochrome A

Planta ◽  
1996 ◽  
Vol 200 (1) ◽  
Author(s):  
J.J. Casal ◽  
R.C. Clough ◽  
R.D. Vierstra
Keyword(s):  
Red Light ◽  
High Irradiance ◽  
Phytochrome A ◽  
Wild Type

Phytochromes and seed germination

1998 ◽  
Vol 8 (3) ◽  
pp. 317-329 ◽  
Author(s):  
Jorge J. Casal ◽  
Rodolfo A. Sánchez
Keyword(s):  
Seed Germination ◽  
Red Light ◽  
High Irradiance ◽  
Phytochrome B ◽  
Phytochrome A ◽  
Germination Inhibition ◽  
Growth Capacity ◽  
Small Family ◽  
Recent Advances ◽  
Signalling Process

AbstractThe control of seed germination by red and far-red light is one of the earliest documented phytochrome-mediated processes Phytochrome is now known to be a small family of photoreceptors whose apoproteins are encoded by different genes Phytochrome B (phyB) is present in dry seeds and affects germination of dark imbibed seeds but other phytochromes could also be involved Phytochrome A (phyA) appears after several hours of imbibition and mediates very-low-fluence responses PhyB and other phytochromes different from phyA mediate the classical low-fluence responses The phytochrome involved in high-irradiance responses of seed germination (inhibition of germination under continuous far-red) has not been unequivocally established, although phyA is the most likely candidate Phytochrome can affect embryo growth capacity and/or the constraint imposed by the tissues surrounding the embryo At least in some species, gibberellins participate in the signalling process In the field, phyA has been implicated in the perception of light during soil cultivations, and phyB would be involved in the perception of red/far-red ratios associated with the presence of gaps in the canopy This review describes recent advances in phytochrome research, particularly those derived from the analysis of germination in specific mutants, and their connection with traditional observations on phytochrome control of seed germination

Phytochrome, photosynthesis and flowering of Arabidopsis thaliana: photophysiological studies using mutants and transgenic lines

2001 ◽  
Vol 28 (5) ◽  
pp. 401 ◽  
Author(s):  
David J. Bagnall ◽  
Rod W. King
Keyword(s):  
Arabidopsis Thaliana ◽  
Photoperiodic Response ◽  
High Irradiance ◽  
Phytochrome A ◽  
Wild Type ◽  
Long Day ◽  
Transgenic Lines ◽  
A Minor ◽  
Type Response ◽  
Plant Arabidopsis Thaliana

A number of phytochrome mutants have been examined for involvement in high irradiance (HIR) or red/far-red (R/FR) end-of-day (EOD) photoresponses during flowering of the long-day (LD) plant, Arabidopsis thaliana (L.) Heynh. A large component of phytochrome A (phyA) response is shown to involve an indirect effect via photosynthesis. When grown autotrophically in soil at a low irradiance (80 mol m–2 s–1), the phyA-211 mutant flowered extremely late compared with wild type and its leaf area was halved, both effects being reversed by increase in photosynthetic irradiance. Supplying sucrose via agar led to very early flowering with little indication of an additional direct phyA HIR. For light-stable phytochrome apoprotein mutants (phyB, phyD) or chromophore mutants (hy1, hy2), flowering was early and R/FR photoreversible EOD response was erased. Conversely, flowering was delayed in a transgenic line overexpressing the PHYB apoprotein. The FR EOD promotion of flowering via phyB was retained in darkness, brief night interruptions mimicking LD response. This novel finding emphasizes the importance of phyB-like phytochromes, with phyA acting indirectly. Whether phyB influences time measurement remains uncertain as we found no rhythmicity in this response to night interruptions. Overall, the role(s) of phytochromes in the regulation of flowering of Arabidopsis include EOD phyB-type response, a minor phyA photoperiodic response, and a large indirect phyA effect involving photosynthesis.

Postnatal growth rate and gonadal development in circadian tau mutant hamsters reared in constant dim red light

Reproduction ◽  
2000 ◽  
pp. 327-330 ◽  
Author(s):  
RJ Lucas ◽  
JA Stirland ◽  
YN Mohammad ◽  
AS Loudon
Keyword(s):  
Time Course ◽  
Red Light ◽  
Somatic Growth ◽  
Postnatal Growth ◽  
Gonadal Development ◽  
Testicular Development ◽  
Wild Type ◽  
Similar Time ◽  
Syrian Hamsters ◽  
Body Weights

The role of the circadian clock in the reproductive development of Syrian hamsters (Mesocricetus auratus was examined in wild type and circadian tau mutant hamsters reared from birth to 26 weeks of age under constant dim red light. Testis diameter and body weights were determined at weekly intervals in male hamsters from 4 weeks of age. In both genotypes, testicular development, subsequent regression and recrudescence exhibited a similar time course. The age at which animals displayed reproductive photosensitivity, as exhibited by testicular regression, was unrelated to circadian genotype (mean +/- SEM: 54 +/- 3 days for wild type and 59 +/- 5 days for tau mutants). In contrast, our studies revealed a significant impact of the mutation on somatic growth, such that tau mutants weighed 18% less than wild types at the end of the experiment. Our study reveals that the juvenile onset of reproductive photoperiodism in Syrian hamsters is not timed by the circadian system.

scholarly journals Recent Progress in the Study of Peroxiredoxin in the Harmful Algal Bloom Species Chattonella marina

Antioxidants ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 162
Author(s):  
Yohei Shimasaki ◽  
Koki Mukai ◽  
Yuki Takai ◽  
Xuchun Qiu ◽  
Yuji Oshima
Keyword(s):  
Oxidative Stress ◽  
Growth Phase ◽  
Critical Role ◽  
High Irradiance ◽  
Growth Potential ◽  
Exponential Growth Phase ◽  
Wild Type ◽  
Chattonella Marina ◽  
Strong Light ◽  
Expression Strain

Peroxiredoxin (Prx) is a relatively recently discovered antioxidant enzyme family that scavenges peroxides and is known to be present in organisms from biological taxa ranging from bacteria to multicellular eukaryotes, including photosynthetic organisms. Although there have been many studies of the Prx family in higher plants, green algae, and cyanobacteria, few studies have concerned raphidophytes and dinoflagellates, which are among the eukaryotic algae that cause harmful algal blooms (HABs). In our proteomic study using 2-D electrophoresis, we found a highly expressed 2-Cys peroxiredoxin (2-CysPrx) in the raphidophyte Chattonella marina var. antiqua, a species that induces mass mortality of aquacultured fish. The abundance of the C. marina 2-CysPrx enzyme was highest in the exponential growth phase, during which photosynthetic activity was high, and it then decreased by about a factor of two during the late stationary growth phase. This pattern suggested that 2-CysPrx is a key enzyme involved in the maintenance of high photosynthesis activity. In addition, the fact that the depression of photosynthesis by excessively high irradiance was more severe in the 2-CysPrx low-expression strain (wild type) than in the normal-expression strain (wild type) of C. marina suggested that 2-CysPrx played a critical role in protecting the cell from oxidative stress caused by exposure to excessively high irradiance. In the field of HAB research, estimates of growth potential have been desired to predict the population dynamics of HABs for mitigating damage to fisheries. Therefore, omics approaches have recently begun to be applied to elucidate the physiology of the growth of HAB species. In this review, we describe the progress we have made using a molecular physiological approach to identify the roles of 2-CysPrx and other antioxidant enzymes in mitigating environmental stress associated with strong light and high temperatures and resultant oxidative stress. We also describe results of a survey of expressed Prx genes and their growth-phase-dependent behavior in C. marina using RNA-seq analysis. Finally, we speculate about the function of these genes and the ecological significance of 2-CysPrx, such as its involvement in circadian rhythms and the toxicity of C. marina to fish.

Far-Red Light Blocks Greening of Arabidopsis Seedlings via a Phytochrome A: Mediated Change in Plastid Development

1996 ◽  
Vol 8 (4) ◽  
pp. 601 ◽  
Author(s):  
Simon A. Barnes ◽  
Naoko K. Nishizawa ◽  
Ronaldo B. Quaggio ◽  
Garry C. Whitelam ◽  
Nam-Hai Chua
Keyword(s):  
Red Light ◽  
Phytochrome A ◽  
Plastid Development

scholarly journals High-Irradiance Response Signaling Is More Ancient Than Phytochrome A

2013 ◽  
Vol 25 (1) ◽  
pp. 3-3
Author(s):  
Kathleen L. Farquharson
Keyword(s):  
High Irradiance ◽  
Phytochrome A

Two native types of phytochrome A, phyAʹ and phyAʺ, differ by the state of phosphorylation at the N-terminus as revealed by fluorescence investigations of the Ser/Ala mutant of rice phyA expressed in transgenic Arabidopsis

2018 ◽  
Vol 45 (2) ◽  
pp. 150 ◽  
Author(s):  
Vitaly A. Sineshchekov ◽  
Larissa A. Koppel ◽  
Cordelia Bolle
Keyword(s):  
Transgenic Arabidopsis ◽  
Emission Spectra ◽  
Total Content ◽  
The State ◽  
Serine Phosphorylation ◽  
Phytochrome A ◽  
Wild Type ◽  
Etiolated Seedlings ◽  
Pre Treatment

Phytochrome A (phyA) mediates different photoresponses what may be connected with the existence of its two types, phyAʹ and phyAʹʹ, differing by spectroscopic, photochemical and functional properties. We investigated a role of phyA phosphorylation in their formation turning to transgenic Arabidopsis thaliana (L. Heynh.) phyA or phyAphyB mutants overexpressing rice wild-type phyA (phyA WT) or mutant phyA (phyA SA) with the first 10 serines substituted by alanines. This prevents phyA phosphorylation at these sites and modifies photoresponses. Etiolated seedlings were employed and phyA parameters were evaluated with the use of low temperature fluorescence spectroscopy and photochemistry. Germination of seeds was induced by white light (WL) pre-treatment for 15 min or 3 h. Emission spectra of rice phyA WT and phyA SA were similar and their total content was comparable. However, the phyAʹ/phyAʹʹ proportion in phyA WT was high and varied with the duration of the WL pre-treatment, whereas in phyA SA it was substantially shifted towards phyAʹʹ and did not depend on the pre-illumination. This suggests that phyA SA comprises primarily or exclusively the phyAʹʹ pool and supports the notion that the two phyA types differ by the state of serine phosphorylation. phyAʹʹ was also found to be much more effective in the germination induction than phyAʹ.

scholarly journals Light Gradient-Based Screening of Arabidopsis thaliana on a 384-Well Type Plant Array Chip

Micromachines ◽  
2020 ◽  
Vol 11 (2) ◽  
pp. 191
Author(s):  
Youn-Hee Park ◽  
Je-Kyun Park
Keyword(s):  
Arabidopsis Thaliana ◽  
White Light ◽  
Solid Medium ◽  
Red Light ◽  
Phytochrome B ◽  
Wild Type ◽  
Light Gradient ◽  
Gradient Based ◽  
Light Effects ◽  
Germination And Growth

Arabidopsis thaliana (Arabidopsis), as a model for plant research, is widely used for various aspects of plant science. To provide a more sophisticated and microscopic environment for the germination and growth of Arabidopsis, we report a 384-well type plant array chip in which each Arabidopsis seed is independently seeded in a solid medium. The plant array chip is made of a poly(methyl methacrylate) (PMMA) acrylic material and is assembled with a home-made light gradient module to investigate the light effects that significantly affect the germination and growth of Arabidopsis. The light gradient module was used to observe the growth pattern of seedlings according to the intensity of the white light and to efficiently screen for the influence of the white light. To investigate the response to red light (600 nm), which stimulates seed germination, the light gradient module was also applied to the germination test. As a result, the germination results showed that the plant array chip can be used to simultaneously screen wild type seeds and phytochrome B mutant seeds on a single array chip according to the eight red light intensities.

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